Production of unique yarns



p 1970 J. F. LONDON, JR, AL 3,526,084

PRODUCTION OF UNIQUE YARNS Filed Dec. 11, 1967 Li X INVENTORS ATTORNEY S United States Patent 3,526,084 PRODUCTION OF UNIQUE YARNS Joe F. London, Jr., and James L. Taylor, Greensboro,

N.C., assignors to Burlington Industries, Inc., Greensboro, N.C., a corporation of Delaware Filed Dec. 11, 1967, Ser. No."689,368 Int. Cl. D02g 3/04; D03d 15/00 US. Cl. 57-140 Claims ABSTRACT OF THE DISCLOSURE This invention relates to the production of crepe-like fabric. More particularly the present invention relates to the manufacture of crepe-like fabric having a hand that is dryer, crisper and loftier than crepe-like fabrics produced heretofore.

Known methods of producing crepe-like fabrics have included the use as weft or filling, or both filling and warp, two kinds of thread, each highly twisted, the twist of one being in the opposite direction to that of the other. Still other methods have utilized chemical treatment procedures on portions of acetate artificial silk together with chemical shrinkage agents. It has also been known to produce a crepe-like fabric from regenerated cellulose yarn containing two types of filaments, one of a high orientation and another of low orientation and wherein the yarn has a twist level in the order to 20 turns perinch or more. In another known method a non-preshrunk polyamide yarn twisted with 12 turns per inch anda fully shrunk yarn also twisted with 12 turns per inch are doubled together with a twist of 25 turns per inch. Before or after being woven or knitted into a fabric the doubled yarn is heat treated to cause shrinkage of the non-preshrunk component to produce a crepe-like effect.

Such known methods of producing crepe-like fabrics suffer from one or more disadvantages including high production costs, the requirement of differently shrinking filling and warp yarns or the requirement of using two or more warp beams in the manufacture of the fabric.

It has now been found that an efficient and highly economical method of producing a crepe-like fabric is possible by plying at least one yarn having substantially no twist prior to plying with at least one of another yarn also having substantially no twist prior to plying, said one and another yarns having different shrinkage properties, subjecting the plied yarns to a twisting operation wherein a twist level ranging from 5 to 15 turns per inch is placed in the composite yarn and heat setting the composite yarn.

As stated above, the yarns utilized in the present invention must have different shrinkage properties. Thus, in one embodiment, any type of yarn which shrinks in the presence of heat can be utilized where one component of the composite yarn is preshrunk and is plied with another component in the natural or non-shrunk condition.

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In another embodiment one component yarn can exhibit a shrinkage value different from the other component yarn in the presence of heat even though both components are heat shrinkable or in yet another embodiment, one of the component yarns can elongate in the presence of heat while the other component shrinks or remains substantially constant. In still another embodiment of the invention, one of the component yarns can shrink in the presence of heat while the other component can be one which remains essentially constant.

Accordingly, the component yarns can be natural or synthetic fibers such as cotton, wool, silk, polyesters, polyamide, acrylic fibers, polyhydrocarbon fibers, cellulose derivatives or the like. When both yarns are of the same type then one component must be treated to modify its shrinkage characteristics so that it will exhibit differential shrinkage properties when plied with and subsequently heat treated with the other component yarn. Specific combinations of component yarns include preshrunk polyethylene terephthalate-non-preshrunk polyethylene terephthalate; polyhexamethylene adipamidepolyethylene terephthalate; acetate-polyethylene terephthalate.

In the plying operation, the twist imparted to the combined yarns, each of which prior to plying are substantially free from having had any twist imparted thereto, is of a relatively low order, i.e. from about 5 to 15 turns per inch and preferably between 8 to 12 turns per inch. It has been found that a twist level bleow about 5 turns per inch does not produce acceptable crepe characteristics while a twist level above about 15 turns per inch diminishes the crepe effect due to the high frequency and low amplitude of the waves produced.

The plying operation can conveniently be combined with a heating operation for modifying the shrinkage properties of oneof the component yarns according to the process represented in the drawing which is a diagrammatical sketch or flow sheet of one embodiment of the invention. In the drawing one of the component yarns 2 is drawn from a creel supply package 4 and passes over conventional tension means 6. Intermediate the tension means 6 and the creel supply package 4 and in the path of the movement of yarn 2 there is provided conventional heating means 8 such as a heater can or the like to shrink or modify the shrinkage characteristics of yarn 2 while in a substantially unrestrained state.

The temperature utilized in this shrinkage operation will be dependent on, for instance, such factors as the particular yarn employed, the amount of twist to be imparted to the combined yarns and the residence time of the yarn within the heater can, or in other words, the exposure time of the yarn to the heat. In all cases, however, the temperature chosen is that which provides, essentially, minimum residual shrinkage with minimum or essentially no damage to the yarn.

From creel supply package 4' there is delivered to tension means 6 another component yarn 2' whose shrinkage characteristics remain essentially unchanged prior to the plying operation. From the tension means 6, the yarns 2 and 2' are brought together through guide means 10 and pass over delivery rolls 12 and 14 from which the combined yarns are forwarded to a conventional ring type twister 16. The twist imparted to the combined yarns at the ring twister ranges from 5 to 15 and preferably from 8 to 12 turns per inch.

Following the twisting operation, the combined yarn can be woven to produce, for instance, a plain weave fabric although it will be recognized that other weaves such as sand crepe weaves can also be effected with the novel composite yarn of this invention. The resulting fabric is then heat set in an unrestrained condition by conventional means, e.g. the fabric can be subjected to steam for a period of time and at a temperature sufficient to allow shrinkage of the fabric wherein one of the two plies shrinks more than the other. This causes the other ply to buckle, which buckle configuration is set by the heating operation thus producing a crepe effect which runs substantially perpendicularly to the direction of the yarn having the differential shrinkage.

As an alternative to the steaming operation, the fabric can be heat set by subjecting it to infrared heat, hot air, hot inert gas or hot fluids such as boiling water, inert organic liquid and the like. The temperature employed during heat setting will be dependent on a number of easily ascertainable factors such as the particular component yarns chosen. The exact temperature of course, should not exceed that which would materially degrade either component yarn. The time of the heat setting operation generally is proportional to the temperature employed, i.e. at lower temperatures a long heat treating period is premissible 'while at higher heat setting temperatures a shorter period of time of exposure is advisable.

The resulting fabric has a much improved hand which is dryer, crisper and loftier than the soapy slick hand of conventional continuous filament fabrics. Further, the appearance of a fabric made in accordance with this invention is much more opaque than a conventional continuous filament fabric and the crepe effect produced is stable to washing and ironing.

The following examples will serve to illustrate the invention without limiting the same.

EXAMPLE I Polyethylene terephthalate yarn (Type 26-Dacron) is used as a supply yarn on both creels 4 and 4'. Yarn 2 is passed through a heater can 8, maintained at a temperature of 575 F. at a rate of 33 yards/min. and delivered to tension means 6. At the same time yarn 2 is passed to tension means 6 at essentially the same speed. Both component yarns 2 and 2 are essentially unrestrained in the travel to the tension means 6 where they are combined.

Thereafter the combined yarns pass through a guide means 10 and over delivery rolls 12 and 14 from which the combined yarns are forwarded to the ring twister 16 where a twist of S turns per inch is imparted to the composite yarn. The ring twister had a spindle speed of 6000 r.p.m.

A plain weave fabric containing 110 ends per inch in the Warp and 60 ends per inch in the filling is prepared from the yarn using a 30 denier nylomist warp. Samples of the fabric were then dry heat set in an unrestrained condition at temperatures of 290 F., 340 F. and 390 F. for 1 /2 minutes, 1 /2 minutes and l /2 minutes, respectively. While the shrinkage of the samples increased as the emperature was increased, all three samples exhibited essentially the same degree of crepe effect. The hand of the fabric samples was dry and crisp as opposed to the soapy hand of conventional continuous filament Dacron fabrics.

EXAMPLE II The procedures of Example I were repeated except that the combined yarn was given a twist of 8 Z turns per inch at the ring twister 16. The combined yarn was woven into a plain weave fabric and dry heat set at 290 F. Similarly favorable crepe eifect and hand were produced in the fabric.

4 EXAMPLE III Again, the method outlined in Example I was repeated except that the combined yarns were given a twist of 2 S turns per inch at the ring twister 16'. A plain Weave fabric produced from this yarn and heat set in an unrestrained condition at 290 F. for a period of 1% minutes to obtain maximum shrinkage of the yarn did not produce an acceptable crepe effect.

'EXAMPLE IV Utilizing the method of Example I, a polyam-ide yarn (polyhexamethylene adipamide) was plied with a polyethylene terephthalate yarn which had been preshrunk by passage through a heater can as previously described. Both component yarns prior to being combined were substantially free from any twist whatever. After combination and delivery to the ring twister 16 having a spindle speed of 6000 r.p.m., the combined yarns were given a twist of 15 Z turns per inch.

The resulting yarn is used to weave a sand crepe woven fabric which is then dry heat set in an unrestrained condition at a temperature of about 290 F. for about 1 /2 minutes. A highly desirable crepe effect and hand are thus produced in the fabric.

Additional and similarly heat set fabrics are woven from a composite yarn made up of a polyethylene terephthalate yarn plied with an acetate yarn and given a twist of 5 S turns per inch; a preshrunk polyhexamethylene adipamide yarn plied with a non-preshrunk polyhexamethylene adipamide yarn which is given a twist of 12 S turns per inch; an acrylonitrile yarn having at least acrylonitrile in the polymer which had been preshrunk and plied with a non-preshrunk polyethylene terephthalate yarn, the composite yarn being given a twist of 12 Z turns per inch; and other combinations including cotton, silk and cellulose derivative yarns with preshrunk polyethylene terephthalate, polyhexamethylene adipamide and acrylonitrile yarns.

It is to be understood that the foregoing description is merely illustrative of the preferred embodiment of the invention of which many variations may be made by those skilled in the art within the scope of the following claims without departing from the spirit thereof.

What is claimed is:

1. A process for producing a woven fabric having a crepe-like effect comprising plying at least one yarn having substantially no twist with at least one of another yarn having substantially no twist, said one and another yarns having different shrinkage properties, sub jecting the resulting composite yarn toa twisting operation wherein a twist level ranging from about 5 to 15 turns per inch is placed in said composite yarn, weaving said composite yarn in a woven fabric and heat setting said woven fabric.

2. The process of claim 1 wherein the twist level ranges from about 8 to 12 turns per inch.

3. The process of claim 1 wherein said one yarn is heat treated in an essentially unrestrained condition prior to said plying with said another yarn at a temperature and for a time to shrink said one yarn.

4. The process of claim 3 wherein said one yarn and said another yarn are both a polyester yarn.

5. The process of claim 4 wherein said polyester yarn is polyethylene terephthalate.

6. A woven fabric made in accordance with claim 1.

7. A process for producing a composite yarn for use in producing woven fabrics having a crepe-like effect comprising heat shrinking at least one heat shrinkable yarn having substantially no twist in an essentially unrestrained condition, plying the resulting heat shrunk yarn with another yarn having substantially no twist and having shrinkage property different from said heat shr-unk yarn and subjecting the resulting composite yarn to a twisting operation wherein a twist level ranging from posite yarn.

8. The process of claim 7 wherein said heat shrinkable yarn is polyethylene terephthalate and said another yarn is natural polyethylene terephthalate.

9. The process of claim 7 wherein the twist level ranges from about 8 to 12 turns per inch.

10. A composite yarn made in accordance with the process of claim 7.

References Cited UNITED 6 Pierce et a1. 57-140 Knospe 57-140 Cruz 139-426 XR Koga et a1. 57-157 Sherer 57-140 Reese 57-140 FOREIGN PATENTS DONALD E. WATKINS, Primary Examiner US. Cl. X.R. 

